Rail vehicles can operate simply in two states, of which, a first one is a straight running state, and a second one is a curve running state. In the prior art, a rubber arm is usually used to connect a wheel to a bogie, such that the vehicle can travel quickly and stably along the rail in the straight running state, and turn smoothly along the rail in the curve running state.
In order to enable the vehicle to operate stably in the straight running state, the rubber arm is usually configured to have a relatively large stiffness. However, such a rubber arm with relatively large stiffness will result in severe abrasion of the wheel and the rail in the curve running state, thereby increasing operation costs of the vehicle.